1. Field of the Invention
The present invention relates generally to light-emitting diode (LED) assemblies, and more particularly to an LED assembly with improved heat dissipation ability so that heat generated by the LEDs of the assembly can be effectively removed. The present invention relates also to a method for making the LED assembly.
2. Description of Related Art
Light-emitting diode (LED) is a highly efficient light source currently used widely in such field as automobiles, screen displays, and traffic light indicators. When the LED gives off light, heat is also produced.
Generally an LED assembly includes a plurality of LEDs mounted on and electronically connected with a printed circuit board (PCB). A heat sink made of metal, such as aluminum or copper, is arranged under the PCB to remove the heat generated by the LEDs. To reduce thermal resistance between the heat sink and the PCB, thermal interface material, such as thermal grease, is often applied between the heat sink and the PCB. However, the thermal grease has a heat transfer coefficient generally not larger than 5 W/(m·K), which is much smaller than that of the metal. Furthermore, as the PCB is made of FR-4, which is produced by glass fiber impregnation into ethoxyline, thermal resistance of the PCB is very large. The heat generated by the LEDs is thus is only very slowly transferred to the heat sink through the PCB and the thermal grease. The heat thus cannot be rapidly and efficiently removed, which results in significant reductions in the lifespan of the LEDs.
Therefore, it is desirable to provide an LED assembly wherein one or more of the foregoing disadvantages may be overcome or at least alleviated.